VIPERS-like mock catalogs

This WEB page details the steps to produce mocks VIPERS-like catalogs, mimicking real VIPERS observations. These realistic mocks reproduce both the color selection and its effects on the redshift distribution of observed data, and the biases in slit positioning introduced by SSPOC, the slit positioning software, and its effects on the Ra-Dec distribution of the observed data.

The starting catalogs were the first five 7X1 sq degs catalogs listed in the VIPERS section of the Virgo Millennium Database web pages (VIPERS_001 to VIPERS_005) - see this website for more informations.

The cosmology adopted in the simulations is Ωm = 0.25,  ΩΛ= 0.75,  Ωb = 0.045, h = 0.73, σ8  =0.9, n=1.

From these 5 catalogs we obtained 10 catalogs limited to 22.5 in i-band (AB, CFHTLS) magnitude (the same limit adopted for our VIPERS observations) and applying an offset to their Ra-Dec coordinates to position them at the centers of the observed W1 and W4 fields. These 10 catalogs are listed in the first column of the Table at the end of this web page.

Notice that catalogs differing only for the string W1/W4 in their name contain the same set of simulated galaxies, but offset in their Ra-Dec coordinates to position then in the areas of the observed W1 and W4 fields.

Each file contains for each galaxy an ID number, Ra, Dec, apparent redshift (cosmological+peculiar motions), i-band observed AB CFHTLS magnitude, b-band rest frame magnitude (AB, dust included).

No error in redshift measurement was added to the apparent redshift, as the error estimate is still uncertain (approx 135 km/sec at z~0, as obtained from repeated measurements of objects in our survey, see this plot).

From now onwards we will call these catalogs: complete 22.5 mock catalogs.

These complete catalogs need to be trimmed in redshift in order to obtain the correct parent mock catalogs for our observations.

Vipers observational strategy includes a color cut intended to remove galaxies located at redshift z< 0.5 from the targets catalog. In practice this color cut translates in a redshift distribution for the observed sample that shows a smooth edge around z ~ 0.5, not mimicked by simply cutting the complete 22.5 mock catalogs at z >= 0.5 (see Figure 1).





Figure 1: Normalized redshift distribution for the observed data (red) and the complete 22.5 mock catalogs cut at z > 0.5 (black). Shaded area corresponds to variance from the two VIPERS fields.

Figure 2: Top: Redshift distribution for the observed data (red) and the complete 22.5 mock catalogs (black). Bottom: ratio between the two distributions. The orange line shows the fit adopted to modulate the redshift distribution of the complete 22.5 mocks.



The mock catalogs to be used as input for SPOC need to reproduce this smoother selection function around z ~ 0.5. The simplest approach is to use just a linear fit to the ratio between the redshift distribution of the observed data and that of the complete 22.5 mock catalogs (this last one normalized in absolute numbers to the observed data in the redshift range 0.6-1.0). Figure 2 shows this fit (orange line in Bottom panel). Error bars on the ratio points are poissonian.

At z > 1 the ratio between the redshift distribution of the observed data and that of the complete 22.5 mock catalogs is consistently lower than 1 (although slightly), possibly a result of our lower success rate in redshift measurements at these redshifts (see also Figure 3).





Figure 3: As Figure 2, but covering a wider redshift range.

Figure 4: Normalized redshift distribution for the observed data (red) and the parent 22.5 mock catalogs (black).



Applying the results of the linear fit to modify the redshift distribution of the complete 22.5 mock catalogs one obtains the results shown in Figure 4, where the two normalized redshift distributions are virtually indistinguishable up to redshift z ~ 1.

From now onwards we will call these catalogs parent 22.5 mock catalogs. They are listed in the second column of the Table at the end of this web page.

From each 22.5 parent mock catalog we then extracted an observed galaxy catalog by applying SPOC. The real data (see Figure 5) display in Ra-Dec the obvious pattern of the VIMOS quadrants and (less noticeable but still present) a pattern due to the slit positioning software SPOC. We reproduced both these patterns applying SPOC to our parent 22.5 mock catalogs, for a total of 33 pointings for field W1 and 31 pointings for field W4 - the number of pointings observed in these two fields as of Jul 2010 (here are the lists used for W1 and for W4). From the output SPOC catalogues we further removed 3 galaxies for each mask (12 galaxies per pointing) to take into account the holes used for the centering. However we did not remove any further galaxy to take into account the actual success rate in redshift measurements.
We will call these catalogs the
observed VIPERS-like mock catalogs (see the third column of the Table at the end of this web page).











Figure 5: Top: Ra-Dec distribution of real data for W1 and W4 fields (as of July 2010). Bottom: Ra-Dec distribution of observed VIPERS-like mock catalogs.



In the following table one can find, for each complete 22.5 mock catalog listed in the Table at the top of this page, the links to the corresponding parent 22.5 mock catalog, and to the observed Vipers-like mock catalog. The header of all these files is always the same (see here).


Complete 22.5 mock catalogs

Parent 22.5 mock catalogs

VIPERS-like mock catalogs

VIPERS_001_22.5_W1.cat

VIPERS_001_22.5_cut_W1.cat

VIPERS_001_W1_Jul2010.cat

VIPERS_002_22.5_W1.cat

VIPERS_002_22.5_cut_W1.cat

VIPERS_002_W1_Jul2010.cat

VIPERS_003_22.5_W1.cat

VIPERS_003_22.5_cut_W1.cat

VIPERS_003_W1_Jul2010.cat

VIPERS_004_22.5_W1.cat

VIPERS_004_22.5_cut_W1.cat

VIPERS_004_W1_Jul2010.cat

VIPERS_005_22.5_W1.cat

VIPERS_005_22.5_cut_W1.cat

VIPERS_005_W1_Jul2010.cat

VIPERS_006_22.5_W1.cat

VIPERS_006_22.5_cut_W1.cat

VIPERS_006_W1_Jul2010.cat

VIPERS_007_22.5_W1.cat

VIPERS_007_22.5_cut_W1.cat

VIPERS_007_W1_Jul2010.cat

VIPERS_008_22.5_W1.cat

VIPERS_008_22.5_cut_W1.cat

VIPERS_008_W1_Jul2010.cat

VIPERS_009_22.5_W1.cat

VIPERS_009_22.5_cut_W1.cat

VIPERS_009_W1_Jul2010.cat

VIPERS_010_22.5_W1.cat

VIPERS_010_22.5_cut_W1.cat

VIPERS_010_W1_Jul2010.cat

VIPERS_011_22.5_W1.cat

VIPERS_011_22.5_cut_W1.cat

VIPERS_011_W1_Jul2010.cat

VIPERS_012_22.5_W1.cat

VIPERS_012_22.5_cut_W1.cat

VIPERS_012_W1_Jul2010.cat

VIPERS_013_22.5_W1.cat

VIPERS_013_22.5_cut_W1.cat

VIPERS_013_W1_Jul2010.cat

VIPERS_014_22.5_W1.cat

VIPERS_014_22.5_cut_W1.cat

VIPERS_014_W1_Jul2010.cat

VIPERS_015_22.5_W1.cat

VIPERS_015_22.5_cut_W1.cat

VIPERS_015_W1_Jul2010.cat

VIPERS_016_22.5_W1.cat

VIPERS_016_22.5_cut_W1.cat

VIPERS_016_W1_Jul2010.cat

VIPERS_017_22.5_W1.cat

VIPERS_017_22.5_cut_W1.cat

VIPERS_017_W1_Jul2010.cat

VIPERS_018_22.5_W1.cat

VIPERS_018_22.5_cut_W1.cat

VIPERS_018_W1_Jul2010.cat

VIPERS_019_22.5_W1.cat

VIPERS_019_22.5_cut_W1.cat

VIPERS_019_W1_Jul2010.cat

VIPERS_020_22.5_W1.cat

VIPERS_020_22.5_cut_W1.cat

VIPERS_020_W1_Jul2010.cat

VIPERS_021_22.5_W1.cat

VIPERS_021_22.5_cut_W1.cat

VIPERS_021_W1_Jul2010.cat

VIPERS_022_22.5_W1.cat

VIPERS_022_22.5_cut_W1.cat

VIPERS_022_W1_Jul2010.cat

VIPERS_023_22.5_W1.cat

VIPERS_023_22.5_cut_W1.cat

VIPERS_023_W1_Jul2010.cat

VIPERS_024_22.5_W1.cat

VIPERS_024_22.5_cut_W1.cat

VIPERS_024_W1_Jul2010.cat

VIPERS_025_22.5_W1.cat

VIPERS_025_22.5_cut_W1.cat

VIPERS_025_W1_Jul2010.cat

VIPERS_026_22.5_W1.cat

VIPERS_026_22.5_cut_W1.cat

VIPERS_026_W1_Jul2010.cat

VIPERS_027_22.5_W1.cat

VIPERS_027_22.5_cut_W1.cat

VIPERS_027_W1_Jul2010.cat

VIPERS_028_22.5_W1.cat

VIPERS_028_22.5_cut_W1.cat

VIPERS_028_W1_Jul2010.cat

VIPERS_029_22.5_W1.cat

VIPERS_029_22.5_cut_W1.cat

VIPERS_029_W1_Jul2010.cat

VIPERS_030_22.5_W1.cat

VIPERS_030_22.5_cut_W1.cat

VIPERS_030_W1_Jul2010.cat

VIPERS_031_22.5_W1.cat

VIPERS_031_22.5_cut_W1.cat

VIPERS_031_W1_Jul2010.cat

VIPERS_032_22.5_W1.cat

VIPERS_032_22.5_cut_W1.cat

VIPERS_032_W1_Jul2010.cat

VIPERS_033_22.5_W1.cat

VIPERS_033_22.5_cut_W1.cat

VIPERS_033_W1_Jul2010.cat

VIPERS_034_22.5_W1.cat

VIPERS_034_22.5_cut_W1.cat

VIPERS_034_W1_Jul2010.cat

VIPERS_035_22.5_W1.cat

VIPERS_035_22.5_cut_W1.cat

VIPERS_035_W1_Jul2010.cat

VIPERS_036_22.5_W1.cat

VIPERS_036_22.5_cut_W1.cat

VIPERS_036_W1_Jul2010.cat

VIPERS_037_22.5_W1.cat

VIPERS_037_22.5_cut_W1.cat

VIPERS_037_W1_Jul2010.cat

VIPERS_038_22.5_W1.cat

VIPERS_038_22.5_cut_W1.cat

VIPERS_038_W1_Jul2010.cat

VIPERS_039_22.5_W1.cat

VIPERS_039_22.5_cut_W1.cat

VIPERS_039_W1_Jul2010.cat

VIPERS_040_22.5_W1.cat

VIPERS_040_22.5_cut_W1.cat

VIPERS_040_W1_Jul2010.cat

VIPERS_041_22.5_W1.cat

VIPERS_041_22.5_cut_W1.cat

VIPERS_041_W1_Jul2010.cat

VIPERS_042_22.5_W1.cat

VIPERS_042_22.5_cut_W1.cat

VIPERS_042_W1_Jul2010.cat

VIPERS_043_22.5_W1.cat

VIPERS_043_22.5_cut_W1.cat

VIPERS_043_W1_Jul2010.cat

VIPERS_044_22.5_W1.cat

VIPERS_044_22.5_cut_W1.cat

VIPERS_044_W1_Jul2010.cat

VIPERS_045_22.5_W1.cat

VIPERS_045_22.5_cut_W1.cat

VIPERS_045_W1_Jul2010.cat

VIPERS_046_22.5_W1.cat

VIPERS_046_22.5_cut_W1.cat

VIPERS_046_W1_Jul2010.cat

VIPERS_047_22.5_W1.cat

VIPERS_047_22.5_cut_W1.cat

VIPERS_047_W1_Jul2010.cat

VIPERS_048_22.5_W1.cat

VIPERS_048_22.5_cut_W1.cat

VIPERS_048_W1_Jul2010.cat

VIPERS_049_22.5_W1.cat

VIPERS_049_22.5_cut_W1.cat

VIPERS_049_W1_Jul2010.cat

VIPERS_050_22.5_W1.cat

VIPERS_050_22.5_cut_W1.cat

VIPERS_050_W1_Jul2010.cat

VIPERS_001_22.5_W4.cat

VIPERS_001_22.5_cut_W4.cat

VIPERS_001_W4_Jul2010.cat

VIPERS_002_22.5_W4.cat

VIPERS_002_22.5_cut_W4.cat

VIPERS_002_W4_Jul2010.cat

VIPERS_003_22.5_W4.cat

VIPERS_003_22.5_cut_W4.cat

VIPERS_003_W4_Jul2010.cat

VIPERS_004_22.5_W4.cat

VIPERS_004_22.5_cut_W4.cat

VIPERS_004_W4_Jul2010.cat

VIPERS_005_22.5_W4.cat

VIPERS_005_22.5_cut_W4.cat

VIPERS_005_W4_Jul2010.cat

VIPERS_006_22.5_W4.cat

VIPERS_006_22.5_cut_W4.cat

VIPERS_006_W4_Jul2010.cat

VIPERS_007_22.5_W4.cat

VIPERS_007_22.5_cut_W4.cat

VIPERS_007_W4_Jul2010.cat

VIPERS_008_22.5_W4.cat

VIPERS_008_22.5_cut_W4.cat

VIPERS_008_W4_Jul2010.cat

VIPERS_009_22.5_W4.cat

VIPERS_009_22.5_cut_W4.cat

VIPERS_009_W4_Jul2010.cat

VIPERS_010_22.5_W4.cat

VIPERS_010_22.5_cut_W4.cat

VIPERS_010_W4_Jul2010.cat

VIPERS_011_22.5_W4.cat

VIPERS_011_22.5_cut_W4.cat

VIPERS_011_W4_Jul2010.cat

VIPERS_012_22.5_W4.cat

VIPERS_012_22.5_cut_W4.cat

VIPERS_012_W4_Jul2010.cat

VIPERS_013_22.5_W4.cat

VIPERS_013_22.5_cut_W4.cat

VIPERS_013_W4_Jul2010.cat

VIPERS_014_22.5_W4.cat

VIPERS_014_22.5_cut_W4.cat

VIPERS_014_W4_Jul2010.cat

VIPERS_015_22.5_W4.cat

VIPERS_015_22.5_cut_W4.cat

VIPERS_015_W4_Jul2010.cat

VIPERS_016_22.5_W4.cat

VIPERS_016_22.5_cut_W4.cat

VIPERS_016_W4_Jul2010.cat

VIPERS_017_22.5_W4.cat

VIPERS_017_22.5_cut_W4.cat

VIPERS_017_W4_Jul2010.cat

VIPERS_018_22.5_W4.cat

VIPERS_018_22.5_cut_W4.cat

VIPERS_018_W4_Jul2010.cat

VIPERS_019_22.5_W4.cat

VIPERS_019_22.5_cut_W4.cat

VIPERS_019_W4_Jul2010.cat

VIPERS_020_22.5_W4.cat

VIPERS_020_22.5_cut_W4.cat

VIPERS_020_W4_Jul2010.cat

VIPERS_021_22.5_W4.cat

VIPERS_021_22.5_cut_W4.cat

VIPERS_021_W4_Jul2010.cat

VIPERS_022_22.5_W4.cat

VIPERS_022_22.5_cut_W4.cat

VIPERS_022_W4_Jul2010.cat

VIPERS_023_22.5_W4.cat

VIPERS_023_22.5_cut_W4.cat

VIPERS_023_W4_Jul2010.cat

VIPERS_024_22.5_W4.cat

VIPERS_024_22.5_cut_W4.cat

VIPERS_024_W4_Jul2010.cat

VIPERS_025_22.5_W4.cat

VIPERS_025_22.5_cut_W4.cat

VIPERS_025_W4_Jul2010.cat

VIPERS_026_22.5_W4.cat

VIPERS_026_22.5_cut_W4.cat

VIPERS_026_W4_Jul2010.cat

VIPERS_027_22.5_W4.cat

VIPERS_027_22.5_cut_W4.cat

VIPERS_027_W4_Jul2010.cat

VIPERS_028_22.5_W4.cat

VIPERS_028_22.5_cut_W4.cat

VIPERS_028_W4_Jul2010.cat

VIPERS_029_22.5_W4.cat

VIPERS_029_22.5_cut_W4.cat

VIPERS_029_W4_Jul2010.cat

VIPERS_030_22.5_W4.cat

VIPERS_030_22.5_cut_W4.cat

VIPERS_030_W4_Jul2010.cat

VIPERS_031_22.5_W4.cat

VIPERS_031_22.5_cut_W4.cat

VIPERS_031_W4_Jul2010.cat

VIPERS_032_22.5_W4.cat

VIPERS_032_22.5_cut_W4.cat

VIPERS_032_W4_Jul2010.cat

VIPERS_033_22.5_W4.cat

VIPERS_033_22.5_cut_W4.cat

VIPERS_033_W4_Jul2010.cat

VIPERS_034_22.5_W4.cat

VIPERS_034_22.5_cut_W4.cat

VIPERS_034_W4_Jul2010.cat

VIPERS_035_22.5_W4.cat

VIPERS_035_22.5_cut_W4.cat

VIPERS_035_W4_Jul2010.cat

VIPERS_036_22.5_W4.cat

VIPERS_036_22.5_cut_W4.cat

VIPERS_036_W4_Jul2010.cat

VIPERS_037_22.5_W4.cat

VIPERS_037_22.5_cut_W4.cat

VIPERS_037_W4_Jul2010.cat

VIPERS_038_22.5_W4.cat

VIPERS_038_22.5_cut_W4.cat

VIPERS_038_W4_Jul2010.cat

VIPERS_039_22.5_W4.cat

VIPERS_039_22.5_cut_W4.cat

VIPERS_039_W4_Jul2010.cat

VIPERS_040_22.5_W4.cat

VIPERS_040_22.5_cut_W4.cat

VIPERS_040_W4_Jul2010.cat

VIPERS_041_22.5_W4.cat

VIPERS_041_22.5_cut_W4.cat

VIPERS_041_W4_Jul2010.cat

VIPERS_042_22.5_W4.cat

VIPERS_042_22.5_cut_W4.cat

VIPERS_042_W4_Jul2010.cat

VIPERS_043_22.5_W4.cat

VIPERS_043_22.5_cut_W4.cat

VIPERS_043_W4_Jul2010.cat

VIPERS_044_22.5_W4.cat

VIPERS_044_22.5_cut_W4.cat

VIPERS_044_W4_Jul2010.cat

VIPERS_045_22.5_W4.cat

VIPERS_045_22.5_cut_W4.cat

VIPERS_045_W4_Jul2010.cat

VIPERS_046_22.5_W4.cat

VIPERS_046_22.5_cut_W4.cat

VIPERS_046_W4_Jul2010.cat

VIPERS_047_22.5_W4.cat

VIPERS_047_22.5_cut_W4.cat

VIPERS_047_W4_Jul2010.cat

VIPERS_048_22.5_W4.cat

VIPERS_048_22.5_cut_W4.cat

VIPERS_048_W4_Jul2010.cat

VIPERS_049_22.5_W4.cat

VIPERS_049_22.5_cut_W4.cat

VIPERS_049_W4_Jul2010.cat

VIPERS_050_22.5_W4.cat

VIPERS_050_22.5_cut_W4.cat

VIPERS_050_W4_Jul2010.cat


At these links you may download the total tar files:

W1_cats.tar.gz, W4_cats.tar.gz, W1_cut_cats.tar.gz, W4_cut_cats.tar.gz, W1_Jul2010_cats.tar.gz, W4_Jul2010_cats.tar.gz.



To obtain fully realistic Vipers-like mock catalog one still needs to add to the catalogs of the third column:

Notice also that catalogs with the same three digit order number are not independent (eg. VIPERS_001_22.5_W1.cat and VIPERS_001_22.5_W4.cat).

For those interested here are fifty files (corresp_VIPERS_001.cat, corresp_VIPERS_002.cat, corresp_VIPERS_003.cat, corresp_VIPERS_004.cat, corresp_VIPERS_005.cat, corresp_VIPERS_006.cat, corresp_VIPERS_007.cat, corresp_VIPERS_008.cat, corresp_VIPERS_009.cat, corresp_VIPERS_010.cat, corresp_VIPERS_011.cat, corresp_VIPERS_012.cat, corresp_VIPERS_013.cat, corresp_VIPERS_014.cat, corresp_VIPERS_015.cat, corresp_VIPERS_016.cat, corresp_VIPERS_017.cat, corresp_VIPERS_018.cat, corresp_VIPERS_019.cat, corresp_VIPERS_020.cat, corresp_VIPERS_021.cat, corresp_VIPERS_022.cat, corresp_VIPERS_023.cat, corresp_VIPERS_024.cat, corresp_VIPERS_025.cat, corresp_VIPERS_026.cat, corresp_VIPERS_027.cat, corresp_VIPERS_028.cat, corresp_VIPERS_029.cat, corresp_VIPERS_030.cat, corresp_VIPERS_031.cat, corresp_VIPERS_032.cat, corresp_VIPERS_033.cat, corresp_VIPERS_034.cat, corresp_VIPERS_035.cat, corresp_VIPERS_036.cat, corresp_VIPERS_037.cat, corresp_VIPERS_038.cat, corresp_VIPERS_039.cat, corresp_VIPERS_040.cat, corresp_VIPERS_041.cat, corresp_VIPERS_042.cat, corresp_VIPERS_043.cat, corresp_VIPERS_044.cat, corresp_VIPERS_045.cat, corresp_VIPERS_046.cat, corresp_VIPERS_047.cat, corresp_VIPERS_048.cat, corresp_VIPERS_049.cat, corresp_VIPERS_050.cat) containing the correspondence between the galaxy IDs quoted in our catalogs and the original galaxy IDs of the mocks in the VIPERS section of the Virgo Millennium Database web pages (VIPERS_001 to VIPERS_050). This original ID number can be used to retrieve from the Virgo Millennium Database any further info desired for each galaxy in our mocks.

Here *pointing info tar file* is a tar file containing for each observed galaxy in these 50 mocks the Pointing and the Quadrant of its VIMOS simulated observations.